MOSCOW, Feb 12 (Reuters) - Russia said on Wednesday it would veto a U.N. resolution on humanitarian aid access in Syria in its current form, denouncing the draft as an effort to lay a foundation for military strikes against President Bashar al-Assad's government.

Moscow had already dismissed the Western-Arab draft debated in the Security Council on Tuesday as a non-starter, but a senior diplomat's unequivocal condemnation indicated Russia would seek major changes before dropping its opposition.

"Its whole purpose and aim is to create grounds for future military action against the Syrian government if some demands it includes are not met," Deputy Foreign Minister Gennady Gatilov said of the draft, according to state-run news agency RIA.

"It is unacceptable to us in the form in which it is now being prepared, and we, of course, will not let it through."

Since the civil war began in Syria in 2011, Russia and China have vetoed three Western-backed Security Council resolutions condemning Assad's government and threatening it with sanctions.

Russia says it is not trying to prop up Assad but that he must not be forced out by foreign powers, and adamantly opposes Western military intervention.

At the United Nations on Tuesday, French Ambassador Gerard Araud told reporters that Russian U.N. Ambassador Vitaly Churkin told the council Moscow was prepared to work on some kind of resolution on aid access, but not the present draft.

Russian Foreign Minister Sergei Lavrov said on Tuesday that Moscow would consider a draft resolution only if it was "not about one-sided accusations" against Syria's government.

The draft condemns rights abuses by Syrian authorities and armed groups, and demands that the government stop all aerial bombardment of cities and towns as well as the indiscriminate use of bombs, rockets and related weaponry. It also condemns "increased terrorist attacks," and calls for the withdrawal of all foreign fighters from Syria.

It expresses an intent to impose sanctions on individuals and entities obstructing aid and if certain demands in the resolution are not met within 15 days of its adoption.

HOMS OPERATION

The government and opposition have agreed on a pause in hostilities to allow the delivery of aid and the evacuation of civilians from Homs, Syria's third-largest city, though aid workers came under attack over the weekend.

Russian officials have said the agreement on Homs has demonstrated that a Security Council resolution is not needed to address the problem at this point, and could serve as a template for similar operations elsewhere in Syria.

Western nations say the Homs operation is a drop in the bucket and want the council to guarantee broad aid access.

On Wednesday, Assad's forces and allied Lebanese militia Hezbollah stepped up attacks on Syria's strategic border town of Yabroud, activists said, in apparent preparation for a new offensive to flush out rebel forces.

While supporting opposite sides in the conflict, the United States and Russia have joined forces to organise peace talks now underway in Geneva and an agreement obliging Assad to abandon his chemical weapons arsenal.

But the aid access dispute has revived mutual recriminations between Washington and Moscow over one another's motives in Syria, where the conflict has killed more than 130,000 people and driven a third of the population from their homes.

"The Security Council needs to speak with one voice," U.S. Ambassador to the United Nations Samantha Power said in a statement on Tuesday. "Every day the council remains silent, we let down the Syrian people, and we fail to uphold our role as guardians of international peace and security."

President Barack Obama said U.S. officials "have delivered a very direct message to the Russians that they cannot say they are concerned about the well-being of the Syrian people when there are starving civilians".

French envoy Araud said the draft was "balanced" but could be amended, suggesting Paris was prepared to accommodate some of Russia's objections in negotiations on the text to avoid a veto.

Gatilov said China agreed with Russia on the draft.

"The Chinese share our approach, and I would like to hope that certain other Security Council members will objectively evaluate the situation," RIA quoted him as saying in Geneva.

However, Chinese Foreign Ministry spokeswoman Hua Chunying spoke cautiously about the draft at a daily news briefing in Beijing on Wednesday, saying: "All parties are currently engaged in talks. We should not prejudge the outcome."

"We believe that at present the international community must work together to relieve the humanitarian situation and should create favourable conditions for the conflicting sides to conduct dialogue and negotiation," she said. (Additional reporting by Michelle Nichols and Louis Charbonneau in New York and Michael Martina in Beijing Writing by Steve Gutterman Editing by Elizabeth Piper)